ASME VIII, I, UG-135 vs API 510

[NewfieEng]

I am in a predicament and I need to hear from the experts.

My customer insistes that there should not be drain hole in the bottom of an ell that is on the discharge piping of our PSVs. He Quotes API 510 where it states that we need either a rain cap or a drain (I don't have API 510 so I cannot confirm that for sure), since we have a rain cap his company (huge international energy Company) wants all PSV to not have a drain hole.

On the other hand our ASME independant code inspector (certifies all out U1As and R1s) states that by ASME VIII, I, UG-135 we need a drain on the ells on the discharge form the PSVs. I have confirmed this and there dosen't seem to be any way to misinterpret this part of the code.

I don't want to piss anyone off since both can affect my work in a huge way. In the oppinion of the expets on this site who is right and who is wrong, or is it not that simple???????

 

[unclesyd]

I would forget API 510 and push for the drain as per code.
The drain prevents liquid from accumulating in the discharge pipe, changing all parameters of the PSV discharge. It is not only rain it can also be liquid from the PSV weeping which they do regularly.

I am assuming that the valves fall under ASME.

 

[DoubleARon]

Fire your inspector, he's full of it. First off I can't find anywhere where 510 states that, possibly its in API 576....

The PSV discharge should have a drain as a minimum, regardless if there is a rain hood or not. The drain is to ensure there is no condensation, rainwater, or liquid from the valve passing from resting on the outlet of the valve. This liquid will do two things, first it will corrode your valve, which could lead to valve malfunction, or improper pop pressure. Secondly, if enough liquid accumulated, it would create a static pressure on the outlet of the valve, and could affect the pop pressure.

 

[DoubleARon]

Oops, not your inspector, he's your customer, guess you can't fire him......

 

[deanc]

Can see you are in a bind. I think you need a drain to comply with the Code. Also see NBIC Appendix I.

Suggestion: You need CYA. Write a nonconformance for this job per your QC System and have the "Owner" sign it,list NBIC I-5900.

Think you may be called back for some rework before they can operate...but you are covered. After all it is thier vessel.

 

[NewfieEng]

I brought up the issue with our customer and he disagreed at first and by the end of the conversation he said he didn't really care if there was a drain hole. So he kind of back pedaled when I told him all about the ASME code and what our inspector said. What a relief.

Thanks for the backup. I thought that ASME would be more stringent and should be followed but I needed some reassurance on my thoughts.